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18650's Care and Maintenance

hello,
i´ve just bouhgt my first 18650 light (fenix TK12 R5), batteries (Trustfire protected) and charger (WF 139).
i have many doubts on the use (charging ,discharging, storing) of this type of battery. i´ve searched in the forum some topic on it but i couldn't find any. i´d appreciate if u guys could help me.

my doubts are;

how should i store my 18650's, charged or discharged?

do they have memory effect? i mean, should i completely discharge them before charging again?

how long can they keep their energy without being used? i mean, would they be ready for use if i store them charged? or i should charge them just before use?

are there any safety reccomendations for charging them, besides not leaving them alone?

do they get too hot while charging? should i place a fan or cooler in front of them while charging?

are there any hints to prolong their life?

my light (fenix tk12) can use either two cr123a or one 18650. what do u think would be the advantages and disadvantages of both?

There are battery experts aboard the forum, but I'll just share what I know

btw,

It is preferred to have the cells charged for storage. Never attempt to completely discharge cells [~3.8V under load]
I've stored my 17670s for a month without significant drop in charge, but then again I'm storing them in a place where its 77F all year and out of the sun. With basic common sense storage practices you should be fine. I bought rechargeables to eliminate my use of CR123As for nightly excursions, so usually my cells are cycled over and over, barely left in storage for half a month.

Since there are many different types of chargers available, I recommend you to read through Mdocod's Consumer Li-Ion "cradle" charger roundup thread to get a better handle on what charger to buy as well as the characteristics of your charger.

Like all batteries, once its capacity is saturated it will begin to convert the additional energy into heat. If your batteries [I'm assuming unprotected] are heating up during charging. It is likely to originate from two possibilities:
the first is your charger is unable to terminate charge accurately. The other is that the charger only has a single channel, but you are charging two cells in parallel and the cells have a different state of charge between each other. This causes one cell to be overcharged and the other undercharged.

I would prefer to have protected cells in my collection because they protect from overcharge and overdischarge by disconnecting the battery

Note that due to internal resistance any battery chemistry will heat up slightly during charge [as well as discharge], this is normal. It should be warm to the touch and not "hot"

Prolonging their life requires some understanding of battery conditioning, and honestly I'm not doing a good job on mine

its debatable on advantages and disadvantages of rechargeables because it involves a couple variables to which you as a user can apply.
If the driver of your light is capable of either, the 18650 is a batter choice, but keep in mind that 2xCR123A has a overall dimension of twice the length of a cr123A, ANSI dimensions as "16340" or 16mm wide, 34mm long, cylindrical. 2xCR123A is then comparable in width to a 16mm wide and approx 68mm long cell. Its closest alternative is actually the 17670 cell. 18650 is the same length but 2mm wider, so normally on lights designed for cr123as 18650s would not fit.

if you use your light only sporadically, rechargeables are not a good investment, especially considering the additional costs of charger and stress .
However, if you use your flashlight every night, rechargeables are the better option because it saves the cost of replacement cells.

There an abundant amount of information on the forum for Li-ions simply because there are so many users here who uses them

Re: 18650's Care and Maintenance

Re: 18650's Care and Maintenance

Originally Posted by Illum

if you use your light only sporadically, rechargeables are not a good investment, especially considering the additional costs of charger and stress.

I would agree with this when using (for example) AA and AAA cells ... My iTP A2s and A3s are used a lot so I always use Eneloops or Hybrios in them ... I also use a few Lithium Primaries AA & AAA (plus spares) in a couple of other torches kept only for emergencies , like in the car.

Unfortunately there is no really compact primary cell to replace my 18650s , so I have to use the Li-Ion rechargeables ... I don't use the three torches (with 18650s) for long periods and I don't recharge them very often ... I probably charge a 18650 every three weeks or so and sometimes even this is before they are fully discharged ... I like the 18650s because I can leave them for months and (if unused) they still measure almost 4.2 volts ... I only check the voltage every three weeks or so ... I realise that it is better to store Li-Ions only partly charged , but I ignore this and keep them fully charged ... My Li-Ions will die of old age rather than due to charging too many times , but I will just replace them every three or four years ... I use Ultrafires so it isn't expensive to replace them.

If anyone is considering using Li-Ion cells , I would suggest that a Digital Voltmeter is bought as this is the only way to tell how much charge is left in the battery ... There are several good threads on CPF about charging and care of Li-Ions and it is essential to read these carefully before embarking on using the Li-Ion cell.

As for the 123 size battery , I would stick to primaries where possible and (preferably) single cell torches ... There again , that is only my opinion.
.

Re: 18650's Care and Maintenance

thank u a lot illum!!! your post was really helpfull!! my light can hold up two cr123a or one 18650. i have already bought some batteries( two TrustFire Protected 18650 3.7V 2400mAh and two TrustFire Primary CR123A) and a charger (Ultrafire WF139). i´m thinking about using primarily the rechargeable 18650 and leaving the cr123a's in my bag as emergency batteries. comparing one 18650 with two cr123a, which do u think would give more power(light) / runtime?

Re: 18650's Care and Maintenance

march.brown, there is some logic to storing cells at a partially charged state...and I think either mdocod or LuxLuthor gave a percentage of the state of charge for long term storage.
You are hopping along in the right direction. Until I can find that value in a post I'm holding off lest to lead anyone in the wrong direction

EDIT: I forgot to mention this great website called battery university, its an added reference to what we on the forum may have missed during our time explaining How to prolong lithium-based batteries

yep, apparently the magic number is 40

If possible, store the battery in a cool place at about a 40% state-of-charge. Some reserve charge is needed to keep the battery and its protection circuit operational during prolonged storage. Avoid keeping the battery at full charge and high temperature. This is the case when placing a cell phone or spare battery in a hot car.

acbezzi, thats where certain members of the forum shines, user Selfbuilt reviewed the TK12 sometime in May and posted a review on it. Like many of his earlier [and later] contributions, it will just about answer all the questions the ower would want to know about the light: output, runtime, ergonomics, etc

to answer your question, referring to Selfbuilt's graphs under the assumption that your TK12 was the same as his
AW protected 18650:
Max 2hr 15min to 50% output
High 7hr 18min to 50% output
Medium 15hr 27min to 50% output

2xCR123A
Max 1hr 54min to 50% output
High 5hr 49min to 50% output

Interestingly as it seems the onboard regulator is designed for 18650s, and the 2xCR123A option is added to which the driver overhead allows.

Personally I found it easier just to carry another light, chances are where you'll need a light you wouldn't be able to see your own hands in front of your face, thats not the best time to lose a tailcap or load cells backwards. I still own carriers though, mostly for bail-out bags and field provisions. While a little expensive, surefires SC1, SC2, SC3 are good battery carriers, very sturdy little guys that holds 4-6cells in pairs, even comes with a o-ring where the threads meet. Only issue for the SC1 is once awhile theres the risk that there will be a crazy TSA agent/border patrol/military nut living next door thinking you're carrying a VS50...which in design it does resemble the VS50, or a plastic shelled anti-personnel mine. So my SC1 mostly stays at home

Re: 18650's Care and Maintenance

Originally Posted by Illum

march.brown, there is some logic to storing cells at a partially charged state...and I think either mdocod or LuxLuthor gave a percentage of the state of charge for long term storage.
You are hopping along in the right direction. Until I can find that value in a post I'm holding off lest to lead anyone in the wrong direction

Hi Illum , I realise that storing Li-Ions in a partially charged condition will give them a longer life , but I'm not worried about gaining a few extra months of cell-life ... I prefer to have all my batteries in a ready-to-use state rather than have to put them on charge before using them ... Personal preference really ... All my LSD AA and AAA cells plus my 18650s are ready to use , even though I don't change them very often.

I check the voltages of the spare Li-Ions every few weeks and today they are either 4.15 or 4.16 volts ... There is one at 4.11 and another at 3.83 but they haven't been charged for quite a few months ... Those two are Ultrafire unprotected (blue) and all the others are Ultrafire protected (grey) ... I don't buy expensive Li-Ions as I will just simply buy more cheapies when these eventually die ... As I said before , this is personal preference and I'm happy with my cell choices so far ... Time will tell.

I also use cheapie protected 18500 Li-Ions in my converted Maglite 2C.

Re: 18650's Care and Maintenance

if you use your light only sporadically, rechargeables are not a good investment, especially considering the additional costs of charger and stress .

When I got my Li-Ion cells I thought that I would get a lot of use out of them, but it turns out that is not the case.

I am now at a point where I wonder if I should have even invested in the Li-Ion cells.
I already sold off my 16340 cells as they were not getting any use.
My 17670 cells get no use because the drivers in the drop-ins in my 6P and G2L won't stay in regulation with a single Li-Ion cell, so those lights now have 2xCR123A primary cells in them.

I like having my lights loaded and ready to go, but I have many lights and it seems that I end up using my AA and AAA lights more than my larger lights most of the time.

With hindsight being 20/20, what I probably should have done was buy a pair of 18650 cells and put the cells in the light that I want to use at the time I want to use it, instead of having a cell for each of the lights.

Re: 18650's Care and Maintenance

Originally Posted by Black Rose

With hindsight being 20/20, what I probably should have done was buy a pair of 18650 cells and put the cells in the light that I want to use at the time I want to use it, instead of having a cell for each of the lights.

I keep my spare 18650s in torches rather than in plastic boxes ... The torches can even be used if necessary.

My main 18650 torches are Solarforce L2's and L2i's , so I can use any one of them ... Unfortunately , I still have some 18650s in plastic storage boxes , though I have just sent for another L2i for $12-56 including postage ... I realise that this is more expensive than a plastic storage box , but it looks better.
.

Re: 18650's Care and Maintenance

Hi Illum,

Keep in mind that the 3V rating on a CR123 cell is different from the 3.7V rating of a li-ion cell. The trend in the industry tends to be that rechargeable cell voltage ratings are closer to their nominal loaded average voltage, while primary cells are often rated closer to their open circuit voltage. In other words.... Getting 4.2WH (8.4WH for a pair) from a CR123 is pretty rare, but getting 9+WH from an 18650 is quite possible.

Re: 18650's Care and Maintenance

Originally Posted by Black Rose

When I got my Li-Ion cells I thought that I would get a lot of use out of them, but it turns out that is not the case.

I know the feeling, but I started out exploring then just stuck to running 17670s in Surefires, not so much for the regulation but for the benefit of whipping out a light that shined as if used with new cells week after week. Gradually I sold/given away the LiCoO2s I didn't use [10440s, 14500s, 18500s] and stuck with cycling two 17670s in Surefire L4s. Several years after I bought my protected 17670 it will still hold a charge, but the runtime is very poor...so I decided to retire them. One of which I have removed the protection PCB, soldered some wires to it, and now became a charging dock for unprotected cells

Its not pretty, but in a single channel DSD featuring a lousy termination point some added protection is always welcome

Originally Posted by mdocod

Hi Illum,

Keep in mind that the 3V rating on a CR123 cell is different from the 3.7V rating of a li-ion cell. The trend in the industry tends to be that rechargeable cell voltage ratings are closer to their nominal loaded average voltage, while primary cells are often rated closer to their open circuit voltage. In other words.... Getting 4.2WH (8.4WH for a pair) from a CR123 is pretty rare, but getting 9+WH from an 18650 is quite possible.

Re: 18650's Care and Maintenance

I also just started using rechargeable batteries specifically an 18650 protected battery from AW. I do have a volt meter and check the voltage regularly but can someone please let me know at what voltage should I not let the battery drop down to before charging?

Re: 18650's Care and Maintenance

Aw protected cells only protect against severe overdischarge and usually will not kick in even when cells have already entered into a deep cycled state. Its designed to kick in to prevent a fire or an otherwise hazardous situation, its not meant for the normal operation ofcells. Likewise so are overcharge protection, only some of the nutcases here [like me] depends on it for normal operation. My take for whats "need recharging" is about 3.9V...

I'm not sure where this came from but I have it taped beside my charger and have been using it for years to manually estimate remaining cell capacity. The capacity of cells to voltage is stated as follows:

Re: 18650's Care and Maintenance

Originally Posted by Mikellen

I also just started using rechargeable batteries specifically an 18650 protected battery from AW. I do have a volt meter and check the voltage regularly but can someone please let me know at what voltage should I not let the battery drop down to before charging?

Thanks.

Most people seem to say ~3.8 volts is a good point at which to recharge Li-ion cells. At 3.8 volts there is approximately 30-40% remaining power in the cell so that gives you some margin of safety. There is no harm in topping up Li-ion batteries that are partially discharged but there is harm in discharging them too low. I would try to avoid ever discharging them below 3.6 volts at which point they are effectively empty.

Various old Fenix models; Zebralight H501w_SC50w+_SC600W; LiteFlux_LF2XT, various Solarforce with XM-L drop-ins.

Re: 18650's Care and Maintenance

I have been using AW protected cells (18650, 17670, 14500 & RCR123's) for over a year now. I usually top them off frequently. After recently acquiring a ZL H30 during use on high the protection circuit kicked in on a 123. Is this cell now compromised? Will it still perform like it did before this event after being recharged? I use a Pila IBC for charging duties.

Re: 18650's Care and Maintenance

Originally Posted by pobox1475

I have been using AW protected cells (18650, 17670, 14500 & RCR123's) for over a year now. I usually top them off frequently. After recently acquiring a ZL H30 during use on high the protection circuit kicked in on a 123. Is this cell now compromised? Will it still perform like it did before this event after being recharged? I use a Pila IBC for charging duties.

By protection kicked in meaning the light was working normally and it just shut off? If so it just means the cell is depleted or shorted somewhere along the way. AW RCR123As according to a couple third party tests appear to be less than ideal for heavy loads and only guarantees a percentive of the "750mah" capacity at moderate loads. How old is your AW cell? as cells age due to cycling it becomes easy for cells to drop in voltage under load than compared to a new cell. I think this is why on laptops as the battery gets old the meter may indicate 100% but when you try and use it it'll run for ~2 minutes then the computer will go out when a new cell pack could last several hours

Re: 18650's Care and Maintenance

Cell was almost new. First time I had one go all the way down. Unfortunately my meters are out of state in storage. I put it on charger and it seemed to charge and terminate normally. Had the ZL on high for about an hour and then it just abruptly went off. In normal uses is it very bad to have the circuit kick in?

Re: 18650's Care and Maintenance

Originally Posted by pobox1475

Cell was almost new. First time I had one go all the way down. Unfortunately my meters are out of state in storage. I put it on charger and it seemed to charge and terminate normally. Had the ZL on high for about an hour and then it just abruptly went off. In normal uses is it very bad to have the circuit kick in?

I wouldn't know because it never happened to me more than once or twice through a couple of years
An hour on high sounds a bit rough though

Re: 18650's Care and Maintenance

Wow, that was a big necropost. The last post was 2-1/2 years ago.

Don't deep-cycle Li-ion batteries, this will shorten their life. Li-ion does not develop memory the way NiCd does.

For modern high-capacity lithium-cobalt cells such as the Panasonic NCR18650B, the optimal open-circult voltage is about 3.6-3.7 V, which represents an approximately 35-45% state of charge. Avoid discharging batteries to below 2.75 V under load or 3.2 V open-circuit, as this will shorten their life as well. Discharging to less than 2.5 V open-circuit will damage the battery and compromise safety, and attempting to recharge a battery at an extremely low voltage (less than 2.0 V) can result in a fire. I would personally try to avoid discharging below 3.5-3.6 V open-circuit whenever possible for optimal service life.

Today's Li-ion batteries are designed to operate to slightly lower voltages, which expains the lower voltages I'm giving. Cells using older technology generally should not be discharged below 3.0 V under load or 3.6 V open-circuit.

Re: 18650's Care and Maintenance

So I should store my 14500 and 10440 Li-Mn and 18650 Li-Ion batteries at 3.6-3.7 V open-circuit? How long will they remain at 3.6-3.7 V before I need to charge them back up to 3.6-3.7? I accidentally posted in this thread instead of creating a new thread.